ArticleEnvironmental advances2024
Seasonal patterns in trace elements assessed in toenails.
Article in Environmental advances, 2024. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
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Who cites it
6 citing papers in PubMed, 3 citations in OpenAlex.
- Association of effort-reward imbalance with fingernail cortisol levels in apparel manufacturing workers.Industrial health · 2026Article
- Changes in community members' toenail metal concentrations after cessation of nearby open-burn thermal treatment of munitions waste.Journal of exposure science & environmental epidemiology · 2026Article
- Toenail metal concentrations and kidney health among young people at risk of chronic kidney disease of uncertain etiology.Environmental epidemiology (Philadelphia, Pa.) · 2026Article
- Manganese pollution in eastern India causing cancer risk.Scientific reports · 2024Article
- Residential proximity to toxic metal-emitting industrial sites and toenail metal concentrations in a United States-wide prospective cohort.Environmental research · 2024Article
- Fingernail Mineral Profiling as a Non-Invasive Tool to Assess Dietary and Lifestyle Factors: Results From the Cross-Sectional Fulda NutriNAIL Study.BioFactors (Oxford, England)Article
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Authors and funding
8 authors at 3 institutions in 1 country.
Funding
Abstract
backgroundSeasonal patterns in measured exposure biomarkers can cause measurement error in epidemiological studies. There is little research about the seasonality of metals and trace elements when assessed in toenail samples. Adjusting for such patterns in models for estimating associations between long-term exposures and health outcomes can potentially improve precision and reduce bias.
objectivesAssess and describe seasonal patterns in toenail measurements of trace elements.
methodsThe Sister Study enrolled women residing in the US, including Puerto Rico, whose sister had been diagnosed with breast cancer. At the time of enrollment, participants removed nail polish and collected their toenail clippings, which were cleaned before analysis. We considered the following elements: iron, vanadium, aluminum, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, tin, antimony, mercury, and lead. For two subsamples of the cohort, we fit trigonometric regression models with toenail element measures as the outcome, using sine and cosine functions of the collection day (transformed to an angle) to capture seasonal patterns. These models can estimate the amplitude and timing of the peaks in measures. We evaluated the evidence for a seasonal effect by comparing for each measured element the trigonometric model to a model that was constant across time.
resultsThere was a seasonal trend in toenail element concentration for iron, aluminum, vanadium, chromium, manganese, cobalt, arsenic, molybdenum, cadmium, tin, and lead, all of which peaked near mid-August. Seasonal patterns were concordant across two non-overlapping samples of women, analyzed in different labs. DISCUSSION: Given the evidence supporting seasonal patterns for 11 of the 17 elements measured in toenails, correcting for seasonality of toenail levels of those trace elements in models estimating the association between those exposures and health outcomes is important. The basis for higher concentrations in toenails collected during the summer remains unknown.
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